GRDC panel member Jon Midwood urges growers to test seed that they plan to use in 2016.
PHOTO: Sharon Watt, Porter Novelli
Growers should test retained seed to ensure they are laying an appropriate foundation for this growing season.
GRDC Southern Panel member and Southern Farming Systems CEO Jon Midwood says seed testing is particularly important after the challenges faced by some growers in 2015.
“Where growers have had particularly tough springs, or have been affected by the Pinery bushfire, it is critical to ensure they are giving themselves the best start for 2016,” he says. “It would add insult to injury to save poor seed and reduce 2016 yields after having a tough season this year.”
Environmental stresses such as dry conditions and heat are known to affect seed formation and can cause reductions in germination and vigour in the seed.
“Some growers may think that using a piece of blotting paper on the window can take the place of a seed test but it does not work,” he says. “Seeds must be tested by a seed laboratory to determine whether the germinating plant has all the essential structures to form a fully viable plant.”
Seed testing key terms
The result will show the percentage of seeds that produce normal seedlings compared with abnormal seedlings and dead seeds under favourable conditions. Abnormal seedlings are those that do not show the potential to develop into a normal plant.
This tests the response of the seed under stress. Seeds are exposed to high temperature and humidity, then subjected to a germination test, and the results compared with the ‘normal’ germination test.
Thousand seed weight
This is the weight of 1000 individual seeds and gives an indication of seed size. Large seeds require higher sowing rates than smaller seeds to give the same plant population.
Laboratory testing assesses the seed under favourable and stressful conditions and measures the size of the seed to ensure the sowing rate is correct.
Mr Midwood says that testing the seed now will give growers the information and time to make the best decision if their seed is found to be wanting: whether it is to buy seed, adjust rotations or accept the risk.
There are three results that determine seed quality: germination, seed vigour and 1000 seed weight. Growers should pay attention to all three results as loss of seed vigour often occurs before loss of germination, and 1000 seed weight affects the sowing rate required.
“The germination test, performed under favourable conditions, may say that the seed will perform well, but if the vigour is low it will have limited tolerance to non-ideal conditions,” Mr Midwood says. “In practice it is rare to have the luxury of sowing in ideal conditions, so while the seed may have a good germination result, if there’s poor seed vigour, the crop is likely to suffer.”
If the seed vigour test results in germination of 10 to 15 per cent lower than the standard germination test, Mr Midwood advises that the weaker seed is sown first in the most ideal conditions. If the vigour test results are more than 15 per cent lower than the germination test, or if the germination is low, he suggests it would be advisable to discard the seeds and purchase higher-quality seed.
“When the seed quality is low, the money saved from not buying seed will almost certainly be lost in poor germination and, as a result, low yields,” he says.
Southern Farming Systems,
03 5265 1666,
Retaining seed fact sheet
Paddock Practices: Retaining the right seed for next year
End of Ground Cover March-April 2016
Read the accompanying Tips & Tactics:
Managing frost risk Tips & Tactics
HRZ disease adapting to drier climes